Respiration is an important physiological activity that helps facilitate metabolism. Monitoring respiratory function is of great clinical significance. Continuous monitoring of respiratory events is also an important clinical requirement as it serves to detect potentially fatal events such as acute respiratory failure as well as pulmonary diseases. Existing methods to obtain patient data relating to respiratory function include devices such as spirometers, chest-belts, impedance pneumography which are contact-based devices. Such devices can be associated with discomfort and psychological dependence. In many diagnosis and therapeutic applications, it is desirable to know the precise intervals of both inspiration and expiration phases of respiration for reasons which include: assessment and intervention prediction for asthmatic and pulmonary patients where the analysis is to be carried out during the expiration phase; respiratory gated acquisition of radiological images where the X-ray device is triggered at a pre-defined phase of the respiratory cycle; and respiratory gated therapeutic shock delivery systems where acoustic shocks are delivered in-phase with the respiratory cycles.
Accordingly, what is needed in this art is a system and method for estimating respiratory phase from a video of a subject.